docs: def clean_text(self, domain, **kwargs):
          """Try to extract only the domain bit from the """
          try:
              # handle URLs by extracting the domain name
              domain = urlparse(domain).hostname or domain
              domain = domain.lower()
              # get rid of port specs
              domain = domain.rsplit(':', 1)[0]
              domain = domain.rstrip('.')
              # handle unicode
              domain = domain.encode("idna").decode('ascii')
          except ValueError:
              return None
          if self.validate(domain):
              return domain